It's not aluminum. It's aluminized mild steel. That's why it's so cheap. Mild steel is very easy to work with, and they "aluminize" it with a sprayed on aluminum coating to provide some resistance to corrosion.
If you live in CA, specifically the Sacramento or Central Valley, you can get the aluminized steel and it will last a very long time. If you are into bling, get the stainless steel. If you live in the MidWest or anywhere you drive on salted roads, definitely get the stainless steel.